Effect of cowpea residue incorporation and nitrogen application rates on the productivity of upland rice

A trial was conducted in 2009 and 2010 at the upland rice field of the Teaching and Research Farms of the University of Agriculture, Abeokuta (Latitude 7 0 2 N and 21 0 E) to investigate effects of cowpea residue incorporation and nitrogen application rates on the productivity of upland rice.The experiment was laid out in Randomized Complete Block Design in split split plot arrangement and replicated three times.The main plot was cowpea incorporation at two levels (Residue incorporated and no cowpea residue incorporated), sub plot was nitrogen application rates ( 0, 20, 40 and 60 Kg N ha -1 ) while in the sub sub plots were the rice varieties (NERICA 2 and ITA 150).Results obtained were subjected to analysis of variance (ANOVA) and significant treatments means were separated using Least Significant Difference (LSD) method.The yield and yield components of rice measured were significantly (P < 0.01) influenced by the incorporated cowpea residue while nitrogen rates had significant (P < 0.01) influence on yield of rice in 2009 and 2010.Rice varieties showed significant (P < 0.01) difference for all traits measured.It is concluded that the incorporation of grain cowpea with nitrogen fertilizer significantly (P <0.01) enhanced the performance of upland NERICA rice.